 The alteration of ion components in the cell and the breakdown of cellular components in the presence of ROS result in the death of affected cells, as well as the formation of local lesions.Reactive oxygen species also trigger the deposition of lignin and callose, as well as the cross-linking of pre-formed hydroxyproline-rich glycoproteins such as P33 to the wall matrix via the tyrosine in the PPPPY motif.These compounds serve to reinforce the walls of cells surrounding the infection, creating a barrier and inhibiting the spread of the infection.